Download of PsychoPy 1.81 for Mac was available from the developer's website when we last checked. We cannot confirm if there is a free download of this app available. Standalonepsychopy-1.81.00.dmg is the frequent file name to indicate this app's installer.
The application is sometimes referred to as "PsychoPy2". We recommend checking the downloaded files with any free antivirus. The software relates to Education Tools. This free software for Mac OS X was originally designed by Jonathan Peirce. The most popular version among PsychoPy for Mac users is 1.8.
From the developer:
PsychoPy is an open-source application to allow the presentation of stimuli and collection of data for a wide range of neuroscience, psychology and psychophysics experiments. PsychoPy combines the graphical strengths of OpenGL with the easy Python syntax to give scientists a free and simple stimulus presentation and control package.
You may want to check out more Mac applications, such as LabAssistant, Schematics Plus or MoonMenu, which might be similar to PsychoPy.